Comparison 13. Subgroup analysis of studies based in Europe.

Outcome or subgroup title	No. of studies	No. of participants	Statistical method	Effect size
1 Mean HbA1c at up to 6 months	2	305	Mean Difference (IV, Random, 95% CI)	‐0.41 [‐0.71, ‐0.10]
1.1 Final values	1	192	Mean Difference (IV, Random, 95% CI)	‐0.34 [‐0.95, 0.27]
1.2 Change scores	1	113	Mean Difference (IV, Random, 95% CI)	‐0.43 [‐0.78, ‐0.08]
2 Mean HbA1c at up to 1 year	1	325	Mean Difference (IV, Random, 95% CI)	‐0.03 [‐0.35, 0.29]
2.1 Final values	0	0	Mean Difference (IV, Random, 95% CI)	0.0 [0.0, 0.0]
2.2 Change scores	1	325	Mean Difference (IV, Random, 95% CI)	‐0.03 [‐0.35, 0.29]
3 Mean HbA1c at 24 months	1	1473	Mean Difference (IV, Random, 95% CI)	‐0.18 [‐0.34, ‐0.01]
3.1 Change value	1	1473	Mean Difference (IV, Random, 95% CI)	‐0.18 [‐0.34, ‐0.01]
4 Final mean knowledge (diabetes and nutrition knowledge) at up to 6 months	2	272	Std. Mean Difference (IV, Random, 95% CI)	0.51 [‐0.19, 1.21]
5 Final mean self‐efficacy and empowerment on diet (can choose correct food) at 6 months	1	192	Std. Mean Difference (IV, Random, 95% CI)	0.95 [0.65, 1.25]
5.1 Final values	1	192	Std. Mean Difference (IV, Random, 95% CI)	0.95 [0.65, 1.25]